Technical analysis, as opposed to fundamental analysis, uses the past price, volume activity, or other measures of a stock, or of a market as a whole, to predict the future direction of the stock or market. The results of technical analysis (sometimes also referred to as “charting”) are usually summarized in charts or graphs that are studied by technicians to identify known trends and patterns in the data to forecast future performance.
Traditionally, the approach to technical analysis is a manual one. One important aspect of technical analysis is pattern recognition in which price information for a period of time is graphed or plotted on a Cartesian coordinate system to facilitate visual recognition of established patterns. For example, FIG. 3 illustrates a classical “head and shoulders” pattern indicating future downward movement of the stock.
Manual charting is a tedious process in which the analyst must create or be provided with a graph of past price information. The analyst must then carefully study the information and determine whether the past price information corresponds with a recognized pattern or formation such as that illustrated in FIG. 3. Although the formation of FIG. 3 may appear to be obvious, this is the final highlighted result. The head and shoulders formation illustrated is much more difficult to recognize from raw data such as that illustrated in FIG. 4.
A manual approach to charting can be unreliable because it depends on human pattern recognition ability. It can be error prone due to guesswork, inaccurate heuristics or the absence of a systematic procedure for comparing the available data with all possible or likely formations.
In addition, if the analyst has a predilection for certain formations, the results may be biased towards those formations and may not be as accurate as an unbiased approach. Finally, a manual approach, even with the aid of mechanical or computer assistance is inherently slow due to the human factor.
A recent innovation in technical analysis is the use of neural networks to recognize patterns in the financial data. However, training neural networks to recognize patterns, or formations, in financial results is cumbersome and highly dependent on the quality of data used to train the neural network.
Graphs of time series, particularly financial time series, sometimes exhibit specific formations prior to moving in a particular direction. Some relevant formations have been described by a number of authors, including Edwards, R. D. and Magee, J. “Technical Analysis of Stock Trends” ISBN 0-8144-0373-5, St. Lucie Press 1998 and Murphy, J. J. “Technical Analysis of the Futures Markets” ISBN 0-13-898008-X, New York Institute of Finance 1986. To anticipate the likely behaviour of some time series, it is advantageous to be able to recognise predictive formations as soon as they occur. Many predictive formations share a common characteristic of being capable of representation by a stylised zig-zag line. Explanations given in Murphy, supra, are largely framed around this concept. It follows that if a method can be found to find suitable zig-zag lines, then the recognition of many predictive formations is greatly simplified. To construct zig-zag lines of a type required to recognise formations, it is particularly useful to categorise time series turning, or pivot, points, as different regions of a formation often require turning points of different strengths. Categorization facilitates the application of appropriate recognition filters to determine the relevance of turning points at various locations in a potential formation.
One well-known technique in technical analysis is point and figure charting. In point and figure charting, the price of, for example, a stock is plotted as columns of rising Xs and falling Os to denote price movement greater than, or equal to, a threshold amount, denoted a box size. Unlike other charting methods, such as open, high, low, close (OHLC), bar or candlestick, where price action is plotted according to time, point and figure charting is more time independent and price, not time, dictates how point and figure charts take shape. For example, a series of volatile trading sessions over the course of a week could fill an entire page or screen in a point and figure chart, whereas a month of inactivity or static range trading might not be reflected on the chart, depending on the chosen box size. The box size determines how much background “noise” is removed from the price action, and, hence, the granularity of the resulting chart. The factors that typically influence the choice of box size include volatility and the time horizon being examined.
The technique of conventional point and figure charting is described in detail in Kaufman, P. J. “Trading Systems and Methods” ISBN 0-413-14879-2, John Wiley & Sons 1996. In summary, a box size, datum price and datum time, are chosen. If a new high exceeds the sum of the current datum plus a box size, a ‘X’ is written in a column and the datum price shifted to the datum plus box size. When the market reverses by more than some multiple of the box size, a column of Os is formed, and continues in a similar manner until the market reverses by more that the prescribed multiple of box sizes. The chart can be based on tick by tick results, or on the OHLC data. In conventional point and figure charting, the use of OHLC data can introduce ambiguity into the charting process, as a large price differentials between high and low in a single day can occur, potentially resulting in a reversal in both directions without it being clear whether the high or low occurred first.
One attractive feature of point and figure charting is the fact that conventionally accepted chart formations, such as double tops and triangles, can be clearly identified. Buy signals can be generated when prices surpass a previous bottom pivot point by one or more boxes, and the reverse for sell signals. This eliminates much of the subjectivity of other analysis techniques. However, point and figure charting is highly dependent on the box size chosen, and relevant formations can be missed if the box size is not appropriate. Some points to note are: (1) point and figure charting conventionally works forwards from a datum rather than backwards from the end of the series. This means that the sequence of X's and O's required to generate a trading pattern depends on the date and price used to start the sequence—which usually results in delayed pattern completion dates, depending on how fortunate the choice of origin was (2) the intention is to produce a chart using a fixed box size, from which a formation will hopefully be recognised visually; (3) the box size acts as a filter, in that small fluctuations in value do not trigger the creation of either a new ‘X’ or ‘O’, but large fluctuations do; and (4) point and figure charts are independent of time, but to create a zig-zag line, time is required. Products available for automating point and figure charting suffer similar disadvantages.
An alternative method is the use of pivot points in the technical analysis of a time series. The time series can include time series of financial data, such as stock prices, medical data, electrocardiogram results, or any other data that can be presented as a time series, and in which it is desirable to identify turning points, trends, formations or other information. The method of pivot points uses a modified point and figure technique to determine the pivot, or turning points, and categorizes them according to the box size at which they appear, while associating time, or lag, information with each identified point. The basic premise is to apply the point and figure charting backwards (i.e. start from the end of a time series and work backwards) using progressively decreasing box sizes, and note the box size at which a turning point first appears on a point and figure chart. The box size provides a measure of a turning point's spatial importance, and so spatial categorization is achieved. Unlike conventional point and figure methods, exact time series values, and lags from the end, are recorded for extreme values associated with each column.
Prior to the actual point and figure charting, the method of categorizing pivot points begins with a spatial categorization of a candidate time series. First, the time series is defined, usually by taking some point of interest from a larger series (henceforth called the “end point”) and a suitable number of prior values to define a search period. The lag of each point with respect to the end point is determined, i.e. the end point has lag=0, the first prior point has lag=1, the second prior point has lag=2, etc.
The maximum and minimum spatial values, MaxY & MinY, of the time series are then determined. The use to which any recognised formation is to be put will normally involve some minimum spatial value. In the example of a price-time series, this will often be a minimum price move that makes a trade worth taking. Some minimal spatial value is, therefore, defined, which will normally be dependent on the intended use of the result. To determine MaxY, the maximum and minimum prices within a search period are found. MaxY is half the difference between these maximum and minimum prices.
Intrinsic noise, INoise, in the time series is then estimated. One way of determining the intrinsic noise is to construct a centred moving average and then find the standard deviation of fluctuations around that average, through the time series. A minimum increment, MinInc, of box size is defined. This can be a multiple or fraction of the minimum spatial value defined above, and is generally dependent on the resolution desired for turning point categorization. Limits for box sizes can then be determined. Point and figure charts have to be created for discrete box sizes, so it follows that suitable limits can be expressed in terms of the number of discrete increments that make up a box. In terms of pseudo code, suitable limits are: trunc(0.5*(MaxY−MinY)/MinInc+1) and trunc(INoise/MinInc+1), for upper and lower limits respectively.
Using the determined upper and lower limits, point and figure charts can now be created, starting with high box sizes and working down to low box sizes in incremental steps. These point and figure charts may be forwards or backwards facing. For price formation recognition methods, backwards-facing charts are generally preferred.
For each box size, the data necessary to create a point and figure chart is determined. Moving backwards through the time series, any new extreme price movements in the same market direction, are noted, together with their associated lag from the end. If the market reverses direction by more than a box size, a new column is created. The extreme value prior to the reversal, and its associated lag, define a turning point. Any turning point that has not been previously found is tagged with the box size, or, in a presently preferred embodiment, the number of increments of the box size, or box size index, for which it is first found and its lag from the end of the series. This results in a set of turning, or pivot, points categorized according to their spatial importance, and their relative time occurrence.
Referring to FIGS. 1 and 2, a method for backwards facing point and figure charting is shown. The flowchart assumes that the lags, minimum box size increment, intrinsic noise, and maximum and minimum spatial values have been determined as described above. While the following description assumes that the time series data includes both high and low values for each time period, continuous data can also be used, in which case the high and low for each time period are considered to be equal. First, at step 101, a pointer to the time series is set to the end point (i.e. the record at lag=0), the box size is set, and the present market direction of the final column, or breakout direction, of the point and figure chart is set. The breakout direction can be either upwards or downwards. In a bull trend, if a reversal formation were sought, the direction of the final column would be set to downwards (i.e. a falling column). In the same bull trend, if a continuation formation were sought, the direction of the final column would be set to upwards (i.e. a rising column). The opposite applies to bear trends. This means that for any given price record and box size, two different point and figure charts can be generated by the method of categorizing pivot points with the choice determined by the purpose to which the chart is to be used.
As shown at step 102, the method of categorizing pivot points proceeds down the left side of the flowchart if the breakout direction is set as upwards or rising, and down the right side of the flowchart if the breakout direction is set as downwards or falling. Assuming that the breakout direction is upwards, in step 103a (and vice versa for step 103b) the end price is set to the current high at lag=0, and the extreme price is set to the current low at lag=0. Initially, both the end lag and extreme lag are set to “0”. Generally, the end price is derived from the most recent price bar associated with the right-most column of the point and figure chart under construction. Extreme price and lag refer to conditions assumed to occur earlier in the development of the column and are recorded to provide a best estimate from which earlier prices can be compared for new extremes or reversals.
The method of categorizing pivot points then enters a loop at step 104 until the time series has been examined for a desired search period where each record in the time series is examined in succession. Again, assuming that the column under consideration has an upwards direction at step 105, the current low of the next record is compared to the extreme price at step 106a. If the current low is less than the extreme price, the extreme price is set to the current low, and the extreme lag is set to the current lag at step 107a, and method moves to the next record in the time series and returns to step 105. If not, the difference between the current high and the extreme price is compared to the selected box size at step 108a. If the difference is less than the box size, no reversal has occurred, and the method again moves to the next record and returns to step 105. If the difference is greater than the box size, a reversal has occurred at this box size and the data necessary to identify the pivot point is recorded at step 109a. The identified pivot point has a price equal to the extreme price and a lag equal to the extreme lag. In general, extremes refer to conditions in the current column and become start prices for a current column, and end prices for the column immediately to its left when a reversal is detected. The column direction is changed as a result of the reversal, and the method moves to previous record (i.e. the next lag) in the time series and returns to step 105 from which it will proceed to step 106b. Steps 106b to 109b are as illustrated, and are the converse of those described above. An additional advantage of producing a point and figure chart in this backwards sense is that the earliest possible pattern completion date is assured, unlike the results of forwards facing charts where pattern completion is dependent on the starting conditions used.
The above described method can then be repeated at each desired box size, preferably from largest to smallest, and the first appearance of a pivot point, and the box size at which it appears can be noted. This results is the categorization of pivot points according to their relative spatial importance, which information can be used most advantageously in subsequent technical analysis formation recognition.